XPS valence band studies of hydrogen storage nanocomposites

In this work, the electronic properties of hydrogen storage LaNi5/A (A = 10 wt.% C, Cu, Pd, Ni) materials and LaNi5+Mg1.5Mn0.5Ni, LaNi3.75Mn0.75Al0.25Co0.25 + Mg1.5Mn0.5Ni nanocomposites were studied. Results showed that the XPS valence bands measured for mechanically alloyed nanocrystalline alloys and nanocomposites showed a significant broadening compared to those obtained for microcrystalline materials with the same chemical compositions. Furthermore, the surface segregation process of La atoms in LaNi5/Pd nanocomposites is stronger compared to that observed for the nanocrystalline LaNi5 alloy thin films.

► The significant broadening of XPS valence bands.
► The surface segregation process of La atoms in LaNi5/Pd nanocomposites.
► Strong modifications of the electronic structure.